Your doctor will ask about your symptoms and your medical history before examining you. Tests usually are needed because the more common symptoms of chest pain and shortness of breath may come from many causes. These tests include an electrocardiogram (EKG), a chest or abdominal X-ray, depending on your symptoms and your physical exam. If these tests show any abnormalities of the lungs or pleura, you will need a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan. These imaging studies allow the physician to determine the size and location of any tumor in the chest or abdomen.

If you have fluid in your chest or abdomen, a thin needle may be used to remove a small sample of the fluid for examination. This procedure, called fine-needle aspiration, also may be used to drain the fluid to relieve symptoms such as chest pain and shortness of breath. Occasionally, mesothelioma can be diagnosed from this fluid sample alone, but usually a tissue sample (biopsy) will have to be taken, too. The tissue sample can be obtained with procedures called a thoracoscopy or video-assisted thoracoscopy (VAT) for a pleural tumor or with a procedure called laparoscopy for an abdominal tumor. In both procedures, a tubelike instrument inserted through a small incision allows the physician to see the tumor and collect a tissue sample. You also may need a procedure called a bronchoscopy or a mediastinoscopy so the doctor can look for masses in the lung airways caused by other tumors or can remove tissue samples from lymph nodes.

There are also some investigational blood tests that may be associated with mesothelioma and can be helpful both in the diagnosis and response to treatment. These are known as osteopontin and mesothelins and are available as part of some clinical studies.

Once your doctor is certain you have malignant mesothelioma, the next step is to determine how far the tumor has spread, which will classify the cancer into one of four stages. This is done with imaging studies, such as CT and MRI. In stage I, the tumor is limited to the pleural lining on one side of the chest without any signs of having spread. If the disease returns after being treated successfully, it is called recurrent mesothelioma.

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